OBJECTIVE To assess the effect of Xianzhen tablet in treating non-insulin dependent diabetes mellitus (NIDDM). METHODS Seventy-two cases of NIDDM patients with deficiency of both Qi and Yin, deficiency of the Kidney and blood stasis were selected, and the effects of treatment on Na(+)-K(+)-ATPase, Ca(2+)-Mg(2+)-ATPase, whole blood viscosity, blood sugar and clinical symptoms were observed. RESULTS After treatment, the treated group showed increased activities that were statistically significant of Na(+)-K(+)-ATPase and Ca(2+)-Mg(2+)-ATPase (P < 0.01, P < 0.02). The whole blood viscosity and symptoms showed improvement to an extent and the total effective rate of blood sugar lowering were as follows: fasting blood glucose (FBG) 77.8%, 2hr. postprandial plasma blood glucose (2hr. postprandial PBG)69.4%. Whereas, the placebo group showed no marked improvement in either whole blood viscosity or symptoms and the total effective rate of blood sugar lowering were FBG 41.7%, 2hr. postprandial PBG 38.9%. CONCLUSIONS Xianzhen tablet is effective in improving the activities of Na(+)-K(+)-ATPase and Ca(2+)-Mg(2+)-ATPase, as well as the whole blood viscosity, blood sugar lowering and in improving clinical symptoms, it could treat effectively NIDDM patients with deficiency of both Qi and Yin, deficiency of the Kidney and blood stasis.